description: The US Core Head Circumference Profile inherits from the US Core Vital Signs Profile. This profile sets minimum expectations for the Observation resource to record, search,  and fetch head circumference observations with a standard LOINC code and UCUM units of measure. It specifies which *additional*  core elements, extensions,  vocabularies, and value sets **SHALL** be present in the resource and constrains how the elements are used. Providing the floor for standards development for specific use cases promotes interoperability and adoption.
package_name: hl7.fhir.us.core
derivation: constraint
name: USCoreHeadCircumferenceProfile
type: Observation
elements:
  code:
    type: CodeableConcept
    short: Head Circumference
    mustSupport: true
    pattern:
      type: CodeableConcept
      value:
        coding:
        - {code: 9843-4, system: 'http://loinc.org'}
    index: 0
  valueQuantity:
    short: Vital Signs Value
    mustSupport: true
    index: 1
    elements:
      value: {type: decimal, mustSupport: true, index: 2}
      unit: {type: string, mustSupport: true, index: 3}
      system:
        type: uri
        pattern: {type: Uri, value: 'http://unitsofmeasure.org'}
        mustSupport: true
        index: 4
      code:
        type: code
        short: Coded responses from the common UCUM units for vital signs value set.
        binding: {strength: required, valueSet: 'http://hl7.org/fhir/ValueSet/ucum-bodylength|4.0.1'}
        mustSupport: true
        index: 5
    required: [value, unit, system, code]
package_version: 8.0.0-ballot
class: profile
kind: resource
url: http://hl7.org/fhir/us/core/StructureDefinition/us-core-head-circumference
base: http://hl7.org/fhir/us/core/StructureDefinition/us-core-vital-signs
version: 8.0.0-ballot